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Top Forums Shell Programming and Scripting Change existing variable value only user enters non-empty string. Post 302423277 by fpmurphy on Thursday 20th of May 2010 02:11:51 PM
Old 05-20-2010
Kchinnam, you are seeing the newlines ('\n") in your od output because you are using the echo command to pipe the variable in question to od. The echo command adds a newline to its output by design.

Try the following example
Code:
uid="scott"
echo "${uid}" |  od -bcx
printf "${uid}" |  od -bcx

gid=
echo "${gid}" |  od -bcx
printf "${gid}" |  od -bcx

Here is the output from this example
Code:
$ ./example
0000000  163 143 157 164 164 012
           s   c   o   t   t  \n
            6373    746f    0a74
0000006
0000000  163 143 157 164 164
           s   c   o   t   t
            6373    746f    0074
0000005
0000000  012
          \n
            000a
0000001
$

 

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ECHO(1) 						    BSD General Commands Manual 						   ECHO(1)

NAME
echo -- write arguments to the standard output SYNOPSIS
echo [-n] [string ...] DESCRIPTION
The echo utility writes any specified operands, separated by single blank (' ') characters and followed by a newline (' ') character, to the standard output. The following option is available: -n Do not print the trailing newline character. This may also be achieved by appending 'c' to the end of the string, as is done by iBCS2 compatible systems. Note that this option as well as the effect of 'c' are implementation-defined in IEEE Std 1003.1-2001 (``POSIX.1'') as amended by Cor. 1-2002. Applications aiming for maximum portability are strongly encouraged to use printf(1) to sup- press the newline character. Some shells may provide a builtin echo command which is similar or identical to this utility. Most notably, the builtin echo in sh(1) does not accept the -n option. Consult the builtin(1) manual page. EXIT STATUS
The echo utility exits 0 on success, and >0 if an error occurs. SEE ALSO
builtin(1), csh(1), printf(1), sh(1) STANDARDS
The echo utility conforms to IEEE Std 1003.1-2001 (``POSIX.1'') as amended by Cor. 1-2002. BSD
April 12, 2003 BSD
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